Flavobacterium arsenitoxidans sp. nov., an arsenite-oxidizing bacterium from Thai soil

An arsenite-oxidizing bacterium, strain S2-3HT, was isolated from arsenic-contaminated soil sample collected from Dantchaeng district, Suphanburi province, Thailand and was characterized based on polyphasic taxonomic study. The strain was observed to be a Gram-stain negative, aerobic, yellow pigmented, non-spore forming and rod-shaped bacterium. Major menaquinone was MK-6. Iso-C15:0, iso-C15:0 3OH, C16:1 ω7c/C16:1 ω6c, C16:0, iso-C17:0 3OH, and C16:0 3OH were the predominant cellular fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, unidentified phospholipids and unidentified aminophospholipids. The DNA G+C content was 37.0 mol%. Phylogenetic analysis using 16S rRNA sequence showed that strain S2-3HT is affiliated to the genus Flavobacterium, and is closely related to F. defluvii KCTC 12612T (97.0 %) and F. johnsoniae NBRC 14942T (97.0 %). The strain S2-3HT could be clearly distinguished from the related Flavobacterium species by its physiological and biochemical characteristics as well as its phylogenetic position and DNA–DNA relatedness. Therefore, the strain represents a novel species of the genus Flavobacterium, for which the name Flavobacterium arsenitoxidans sp. nov. (type strain S2-3HT = KCTC 22507T = NBRC 109607T = PCU 331T = TISTR 2238T) is proposed.